Softly, with Teeth is a story that tries very hard to have a villain. It’s the sort of story that necessitates a murderer simply because we are too cowardice to have Alexander Bernard kill himself. We instead have created a half-baked effort. That is, Diana looks for problems instead of waiting them to come to her, much like any good protagonist.
Charlotte would be a hero in most stories. She is a rebel fighting against an imperfect society, full of passion and caring. However, she does hurt others for it - but in her eyes, much similar to Forrest, there is a distinct dehumanization to vampires.
Charlotte, in the strict context of a SWT device, represents:
1) Full isolation is bad.
Diana’s isolation in the later parts of the story directly lead to her deteriorating mental state and leads to unnecessary tragedy.
2) Escapism is bad if viewed as the end goal and not a means of transition.
Diana does go full biblical angel for a bit in Everard’s route, but it’s a terrible thing to stay in. It’s lonely at the top.
That isn’t to say that anything Charlotte does is particularly more terrible than the things the other vampire have done, or will do. Yvonne and Bernard both have done reprehensible things, and given how politics tend to go, it can be assumed that Forrest probably partakes too. However, she just happened to kill just the right person to galvanize Diana just that little bit more and give her a fleeting excuse.
Even Diana ends up using Charlotte as nothing more than a tool, similar to how we as the team had originally conceived her. She’s a means to an end, unfortunate collateral to the emotional problems of the rest of the cast. It could be argued that she also dragged them into her own emotional problems by being willing to kill a lot of people because she wanted to reverse past mistakes, but, alas.
It can also be argued that it’d be a waste of potential to not be able to turn back time if given the opportunity, much like it’d be viewed as silly to not want to “mess with the time stream” when someone is sent back in time in general. It’s very manifest destiny, in that sense.
Before Charlotte is an antagonist, though she must be a person. She chases nostalgia to degrees as severe as Forrest and Diana, if just not for high school romantics.
It could be said that she craves ignorance, or a version of freedom. Humanity would change very much if we could confirm what happens after we die. Of course in the context of SWT, it’s not as if freedom to not know what happens in the afterlife is necessarily a true freedom, or a malleable truth. At the end of the day, Catherine and Palmer call the shots, both for better and worse.
Maybe she craves companionship. She shouldn’t be faulted for being selective in her taste, because we all are, but there’s a difference between being selective and dismissive. How can someone moan about being lonely if they never reach out to others first?
(So in a case like this, perhaps Diana reaches out first. She usually does, after all.)
Charlotte craves possibility.
Charlotte wishes not to hurt, not to take. It’s a dream to be self-sustainable. Perhaps she was hurt in the past, and pulled in on herself in fear of never being hurt again. Much like Diana, she’s held onto a grudge much longer than she should’ve - or could’ve. (Does someone put themselves through unfortunate trouble more than they absolutely have to? Why so?)
Charlotte doesn’t relish in murder. She has less pride in it, less romanticism in it than Diana does. She still does it, though. She believes herself above others, and acts justly with that in mind, even if it isn’t really true.
Charlotte tries very hard to be a good person, like Forrest, like Diana, and has the nerve - the audacity - to go as far as she possibly could with it.
Charlotte is a romantic, but not into romance. It only makes sense that she is an adversary in Softly, with Teeth. She likely views herself similar to Joan of Arc, or, more accurately, someone like Gilles de Rais, or Hubert von Vestra. Someone who is distinctly not part of the light, someone who is willing to get their hands dirty to protect someone’s light. In this sense, she is more similar to Yvonne than she cares to admit, because that would mean acknowledging that Yvonne’s manipulations can lead to good things. Yvonne plucks strings, Charlotte cuts through the pretension under the pretense of honesty and the value thereof.